A large number of orthopaedic exercise frames are in use, these frames all have a substructure or chassis with a sliding carriage on which a calf support with a foot support is mounted. This carriage is moved by means of a motor-driven spindle. Extension and/or flexing of the leg is accomplished by moving the carriage backwards or forwards, the leg thus being correspondingly extended or flexed. It is also possible, irrespective of this motion, to provide additional active muscle training by having the foot support movable against a additional spring.
In order to attain anatomically correct extension and flexing of the leg in the machines known, it is necessary that the spindle, which is located in the substructure of the carriage, the chassis or the orthopaedic exercise frame have a length of at least 450 mm. The carriage must, therefore, be moved along the length of the spindle in order to achieve a motion of the leg, which permits anatomically correct treatment.
This long backwards and forwards movement causes very high loads on the components exposed to wear. The length of the spindle, furthermore, necessitates a correspondingly large substructure or chassis, which enlarges the orthopaedic exercise frame as a whole, not only its length, but also its weight. The high weight is a particular disadvantage for the staff operating the exercise frame since it is not possible to provide an orthopaedic exercise frame for every patient, so that the frame must, instead, be transported from bed to bed.